Evaporator system for refrigeration



March 12, 1935.

N. H. GAY

EVAPORATOR SYSTEM FOR REFRIGERATION 3'Sheets-Sheet 1 Filed Nov. 15, 1932March E2, 1935. N. H. GAY

EVAPORATOR SYSTEM FOR REFRIGERATION Filed Nov. 15, 1952 3Sheets$heet 2N. H. GAY

EVAPORATOR SYSTEM FOR REFRIGERATION March 12, 1935.

Filed Nov. 15, 1952 5 Sheets-Sheet 3 llllll'l UNITED STATES.

PATENT OFFICE EV APORATOR SYSTEM FOR REFRIGERATION Norman H. Gay, LosAngcles, Calif. Application November 15, 1932, Serial No. 642,802

29 Claims.

The present invention relates to improvements in refrigerating plants,and more particularly r'elates to the evaporating systems employedtherewith.

In my United States Letters Patent #1,836,318 and #l,878,694, I havedescribed ways of employing the energy of the refrigerant itself formaintaining an evaporator in operation, and for separating refrigerantliquid which has passed through the evaporator and returning it in thecircuit.

The present invention relates to evaporator supply systems of thisnature, and further pro-' poses the employment of a top-fed ortrickle-type evaporator, and more specifically, a top-fed ortrickle-type evaporator. in which multiple gas outlets are provided forthe release of gas from the evaporator at intermediate points of thelength thereof.

Other features of the invention reside in the forms of construction andarrangement of the several parts, and will appear in the course of thefollowing specification and, claims.

Illustrative forms of practicing the invention are set forth in theaccompanying drawings, in

which:

Figure 1 is a diagrammatic view showing the association of the severalparts, in the conjunction of an evaporator feeding system of the presenttype and a top-fed or trickle-type evaporator.

Figure 2 is a detail view, on a larger scale, showing a means forregulating the rate of feed in one evaporator coil. I

Figure 3 is a similar detail view showing a permissive modification inthe arrangement of the evaporator coil.

Figure 4 is a diagrammatic view, on a larger scale, showing a modifiedarrangement of expan-' sion valve system and liquid lift.

Figure 5 shows a further modification of these 6, 7 and 8 are similarviews, on the same scale of Figure 1, showing other arrangements of theexpansion valve system, and upper and lower liquid vessels.

18 to the interior of the ejector nozzle 19 located within the lowerliquid vessel 20 which is sealed against the atmosphere. terminatesbelow the normalliquid level in vessel 20 and has its upwardly directednozzle end located within the expanded end of the liquidli ft pipe 21which communicates with the upper liquid vessel 22 above the normalliquid level therein. This normal liquid level is determined in part bythe overflow pipe 23. A gas equalizing pipe 24 provides communicationbetween the top of the lower vessel 20 and the upper vessel 22 at apoint above the normal liquid level in the upper vessel, but below themouth of pipe 21. The operative cross section of the aperture in nozzle19 may be, varied. by the manually regulatable stem 25.

Gas collecting in the upper vessel 22 is drawn off through the returnconduit 26 to the compressor 10.

The liquid flowing from the upper vessel 22 through the overflow pipe 23enters a header 27 which communicates with a plurality of coils ofthetype shown in Figure 1, for example. These coils each "comprise aplurality of runs 30a, 30b, 30c, 30d 30:: which may be formed, forexample, of a single length by rebending it from point to point. It willbe noted that such a coil may be constructed in a single plane andsupported by pairs of uprights 31, 32 which are bolted'together betweenthe runs of the coil. The top run 30a is supplied by an up-comer pipefrom the inlet liquid header 27, this header being located belowthenormal liquid level in vessel 22, while the upper run 30a issubstantially at this level. The ends of the upper run 30a which areopposite the liquid header 27, however, may be adjusted as to its heightby the bolts 33. when this left-hand end of the upper run 30a is at alow level a larger quantity of liquid refrigerant flows through the coilthan when it has been raised, as for example, in the position shown inFigure 2, corresponding to the full line position in Figure 3. It willbe noted that this regulation is accomplished without any telescoping orrelative mechanical movement of independent parts, and aifords an easyand direct manner of regulating the quantity of refrigerant enteringeach coil of a bank, and hence of equalizing the effect of the bank ofcoils.

The lower runs 30c, 30d may be horizontal, or each may have a slightincline to assist the flow of liquid refrigerant through the coil fromits upper to its lower end. At the lower end, the final run 30:: extendsbelow a normal liquid level in the lower liquid vessel 20, so that itslow- The nozzle 19 v mitted to escape into a gas collector pipe 3'7 01'this coil, and thence to the gas outlet or header 38 for the bank ofcoils, and thence by conduit 39 into the upper liquid vessel 22 at apoint above the mouth of the pipe 21. It is preferred to provide abattle 40 in the upper vessel 22 to assure a segregation of gas andliquid in this vessel.

In order to shut off a particular coil of a bank, a valve 41 isprovided, for operation in conjunction with the adjustment bolt 33 ofthis coil.

The lower end of the gas collector pipe 37 is joined to a liquid returnheader 42 and thus to the lower vessel 20 at a point below the liquidlevel therein, so that the liquid level in the lower run 301: and in thegas collector pipe 37 is in correspondence with the level existing inthe lower level 20. Hence, the pipe 24 and thegas collector pipe 37 bothoperate as balancing or equalizing pipes in the system.

The upper vessel 22 preferably extends downward for a distance below theoverflow pipe 23 suflicient to provide a pool for the collection of oil.This upper vessel 27 is desirably of suflicient size to avoid rapidcurrents, and to afford the oil a sufficient time to settle out, wherebythis upper vessel operates as an oil trap in the system. The oil thuscollected may be drawn off through pipe 44, by opening valve 45 fromtime to time as desired.

In the operation of this system, with the compressor' 10 operating andthe liquid refrigerant collecting in the receiver 14, the float valve 15operates as an expansion control valve to permit the flow of liquidrefrigerant at a. temperature corresponding to the temperature of themeans employed for cooling condenser 12, toward the nozzle 19. Therelease of pressure occurring at the expansion valve results in theevaporation of a portion of this liquid refrigerant and the cooling ofthe remainder to a temperature determined by the pressure drop inpassing from the high pressure to the low pressure portions of thesystem. This evaporation gives rise to flash gas and an increase in thevolume of refrigerant vfluid (i. e. mixed gas and liquid) in the nozzle19, and thus results in a jet of fluid moving upwardly in theliquid-lift pipe 21, which draws with it liquid from the lower liquidvessel 20 and delivers the final mixture into the upper liquid vessel22, where it separates into liquid and gas, and attains the low liquidtemperature of the system. The gas returns to the compressor in circuit.The liquid collects, yields off any oil there in; and as the level risesin the upper vessel 22, part of this liquid flows through overflow pipe23 into the liquid inlet header 27 and thus into the evaporator coils,trickling down through these coils and evaporating in proportion to theheat As this trickling liquid evaporates, the gas moves to the multipleoutlet 34, 35, 36, and thus into the gas collector pipe 37 and to theupper vessel 22 and thus back to the compressor. If the coil is alreadyat low temperature, and its regulation permits the delivery of a portionof itsliquid into the bottom run 30:11, the liquid level'in the lowervessel 20 tends to build up, and this liquid is then lifted into theupper vessel 22 for re-circulation through the evaporator. Any gasforming in vessel 20 immediately escapes through the equalizing pipe 24.If too great a level of liquid is built up in the upper vessel 22,tending to flood the evaporator system, it may escape downwardly throughthe equalizing pipe 24 into the lower vessel 20 for re-circulation: butit will be understood that in a closed system, this can only occurmomentarily, as there is then so little gaseous refrigerant that thecompressor is drawing a considerable vacuum and the receiver 14 soonbecomes emptied and no longer delivers liquid into the system. Theevaporator operates at a greater degree since more liquid is present ineach of the runs, and the evaporated gas passes back to the compressorin response to the greater degree of vacuum produced thereby. Theoperation is, therefore, selfcorrective.

It is also possible to operate the system as shown in Figure 1 with theelimination of the floatvalve 15, and with the employment of the manualvalve 17 as the expansion valve. In this event, if the operation of thedevice indicates that too much liquid is entering the evaporating coils,and adjustment of the bolts 33 has been suchthat the coils are operatingat uniform effectiveness, then the partial closing of valve 17 willresult in a correction of the tendency for increase of liquid level.

In the form of construction shown in Figure 4, the evaporator coil,headers and upper vessel are assumed to be the same as in Figure 1. Thelower vessel 20 is likewise substantially identical with that of Figure1, but an electrically ope ated expansion valve 15a is provided, whichopens upon energization of its solenoid 50. The ener- V gization of thesolenoid may be accomplished from battery 51 in various ways. InFigure4, the float 52 within the receiver 14 is connected to a circuitcontrolling switch arm 53 which closes a circuit by conductor 54 toconductor 55 and thence by switch 56 and conductor 5'7 to the solenoid50. Hence the valve 15:; will be operated to open when the level inreceiver 14 rises to a predetermined level: and the valve closesautomatically in the usual manner again, when this level drops until thecircuit is broken at switch 53. However, by moving the switch 56 toanother position, current will flow from conductor 54 through a manuallyclosable remote switch 60 and thence by conductor 55a, switch 56 andconductor 59 to the solenoid 50 for opening the valve. Likewise, inanother position of the switch 56, current will flow from conductor 54when the thermostat element 61 closes its contacts in response to adefinite high temperature, and thence by conductor 55b to switch 56, andultimately to the solenoid 50 to produce an opening of the valve 15a.These forms indicate the possibilities of establishing a remote controlof the system, with the operation of the structure as already describedfor Figure 1.

In Figure 5, a further formjof the invention is shown in which thelowervessel. 20a is provided with the gas equalizing pipe and the liquidequalizing pipe 71 which communicate through shut off valve 70a, 710.with the interior of a valve float chamber 72, which thus is equalizedwith the lower vessel 20a. The liquid conduit 18 from by the needlevalve 74. This needle valve is opened by the action of float when theliquid level falls in the lower vessel 20:: and the float chamber 72,thus'permitting further refrigerant to enter from pipe 18 and passthrough the pipe 76 to the interior of the nozzle 19 of the ejector. Ingeneral, the operation ofthis system is the same as that alreadydescribed with respect to Figure 1, except that the system is automaticin reducing the quantity of liquid which is, admitted to the system, andcontrolling it on the basis of the liquid level in the lower vessel 20a,and hence the head of liquid pressure existing in the liquid header 42.

In the form of execution shown in Figure 6,.the pipe 16a from thereceiver is connected through an electrically actuated valve 15b and themanually operable valve 17a. with the lower vessel 20b, and merelydelivers its mixed gaseous and liquid refrigerant thereinto, without theemployment of ejector action. The flash gas, however, accumulates in thelower vessel 20b so long as the relief valve 80 between the liquidoutlet header 42 and the lower vessel 20b is closed, and oper ates toforce the liquid from the lower vessel 20b through the liquid lift pipe21a into the upper vessel 22a as before, from which it passesby theoverflow pipe 23 into the evaporating coils. This, however, results in acollection of liquid in and above the header 42. To relieve this liquid,the valve 80 is opened from time to time: and if desired theelectrically operated expansion valve 15b is simultaneously closed. Thevalves may,

for-example, be controlled in opposition from -a rotating switch 81which closes a circuit from a battery 82 to the conductors 83 and thusto the control solenoids 84, 85 ofvalves 15b, 80. During the opening ofvalve 80, the liquid flows from the header 42 and the gas collector pipe37 to the lower vessel 20b and flashgas may pass upwardly into gascollector pipe 3'7 and thus into the vessel 22a and back to thecompressor. It is not, however, essential to shut off the expansionvalve 15b in order to establish this balancing effect, but expansionvalve 15b must be open when relief valve 80 is closed.

In Figure 7 a further modification is shown which the lower vessel 200has an ofl'z-set containing a portion of the conduit 18 and a needlevalve 91 controlling the conduit and thus regulating the passage ofrefrigerant from the receiver. This needle valve '91 is connected to afloat 92 located in the lower vessel 20c itself so that the needle valveopens as the level rises in the lower vessel 20c. The mixed liquid andgas passing the needle valve 91 (operating as an expansion valve) flowsthrough pipe 93 into the upper vessel 22 at a point above the normalliquid level therein. The operation of this system is substantially thesame as before, except that the liquid in the lower vessel 20c is notdelivered as such into the upper vessel 22b but is balanced in pressuretherewith by the equalizing pipe 24a which permits the free escape ofgas. An accumulation of liquid in the lower part of the system resultsin a lesser delivery of liquid through the pipe 93 into the upper vessel22b, and hence a lesser flow of liquid to the liquid inlet header 2'7and thus to the evaporating coils-so that the existing condition ofover-supply tends to correct itself.

This same result can be attained, by manual supervision and control inthe form shown in Figure 8, in which the manual valve 1'7 is connectedby pipe 93a to the upper vessel 22c. This manual valve 17 is, forexample, opened or closed as the liquid level rises or falls in the gage95 of the lower vessel 20d.

' Figures 1, 4, 5, and 6 operate by energy liberated in passage fromhigh pressure to low pressure at expansion valve to lift the refrigerantliquid.

It is obvious that while specific types of float valve control are shownat Figures 1, 4, 5 and 7 the various types are interchangeable, and thatelectric types can replace mechanical types or vice versa.

' It is obvious that the invention is not limited solely to the forms ofconstruction shown, but that it may be modified in many ways withoutdeparting from the scope of the appended claims.

Having thus described the invention, what I claim asnew and desire tosecure by Letters Patent, is:

1. In a refrigerating system, an evaporator including a plurality ofsuccessively superimpomd runs each arranged substantially horizontallyand connected in series for the free flow of liquid refrigerantdownwardly from one run to the other, an-upright gas collector pipe, anda plurality of gas outlets connected to runs at different levels and tosaid gas collectorpipe.

2. In a refrigerating system, an evaporator including a plurality ofsuccessively superimposed runs arranged substantially horizontally andconnected in series for the free flow of liquid refrigerant downwardlyfrom one run to the other, an upright gas collector pipe, a plurality ofgas outlets connected to 111118 at different levels and to said. gascollector pipe, and means for supplying liquid refrigerant to the toprun.

3. In a refrigerating system, an evaporator including a plurality ofsuccessively superimposed runs arranged substantially horizontally andconnected in series, an upright gas collector pipe, a

plurality of gas outlets connected to runs at different levels and tosaid gas collector pipe, means for supplying liquid refrigerant to thetop run. and means for raising and lowering the and of said top runremote from the supply means.

4. In a refrigerating system, an evaporator including a coil providing aplurality of runs connected in series, a substantially vertical gascollector pipe, multiple gas outlets extending-from rims at differentlevels to said gas collector pipe, means for supplying liquidrefrigerant into the top runfrom which it may pass successively downwardthrough the runs in series, means for supporting the runs insubstantially fixed position adjacent said supply means, and a devicefor raisingand lowering the connected end of the too run and nextsucceeding run which is remote from the said supply means.

5. In a refrigerating system, an evaporator including a length of piperebent into a plurality of superimposed substantially horizontal runslocated in a vertical plane, a gas collector pipe located substantiallyin saidplane and arranged substantially in a vertical position, and aplurality of gas outlets connected with said gas collector pipe atdifferent levelsand with said rims at different points of height.

6. In a refrigerating system, an evaporator including a plurality ofsuperimposed substantially horizontal rims connected 'in series, avessel ,for

containing liquid refrigerant to a level corresponding to that of thetop r n. and a supp y conduit establishing communication between saidvessel and the top run and including an upwardly extending end whichopens into said vessel.

7. In a refrigerating system, an evaporator including a plurality ofsuperimposed substantially horizontal runs connected in series, a vesselfor containing liquid refrigerant to a level corresponding to that ofthe top run, a supply conduit establishing communication between saidvessel and the top run and including an upwardly extending end openinginto said vessel, and means for bodily raising and lowering the end ofsaid top run remote from the connection of the supply pipe thereto.

8. In a refrigerating system having a compressor, a condenser, atop-feed trickle-type evaporator and conduits for connecting the same incircuit, a vessel interposed in the conduit between the condenser andevaporator, an expansion valve for controlling the flow of refrigerantfrom the condenser into said vessel, and means operated by the transferof refrigerant through said expansion valve from the high pressureportion to the low pressure portion of the system for raisingrefrigerant'from the evaporator outlet into said vessel.

9. A refrigerating system having a compressor, a condenser, a top-feedtrickle-type evaporator, a first vessel for receiving liquid refrigerantfrom the bottom of said evaporator, a second vessel connected to the topof said evaporator to deliver liquid refrigerant thereto and to aplurality of points thereof to receive gaseous refrigerant therefrom, aconduit connecting the gas space of said second vessel with thecompressor, a conduit including an expansion valve for connecting thecondenser and said second vessel, and an equalizer pipe for connectingthe gas spaces of said vessels.

10. In a refrigerating system having a com-- pressor, a condenser, atop-feed trickle-type evaporator and conduits for connecting the same incircuit, a low-level vessel connected to the bottom of the evaporatorfor receiving liquid refrigerant therefrom, a high-level vesselinterposed in the conduit between the condenser and evaporator forsupplying liquid refrigerant to the top of the evaporator, an expansionvalve in said condenser-evaporator conduit for separating the high andlow pressure portions of the system, and means operated by the transferof refrigerant from the high pressure to the low pressure portion of thesystem for raising liquid from the low-level vessel to the high-levelvessel.

11. In a refrigerating systemhaving a comp"essor, a condenser, atop-feed trickle-type evaporator and conduits for connecting the same incircuit, a vessel connected to the bottom of the evaporator forreceiving liquid which has passed through said evaporator, an expansion.

valve located in the conduit between the condenser and evaporator, andejector means operated by the refrigerant passing through said valvetoward said evaporator and serving to raise the liquid from said vessel.

12. In a refrigerating system having a compressor, a condenser, areceiver, a top-feed trickletype evaporator and conduits for connectingthe same in circuit, a valve operated according to the liquid level insaid receiver for controlling the passage of refrigerant from thereceiver toward said evaporator, a vessel connected to the bottom ofsaid evaporator for receiving liquid which has passed through theevaporator, and means operated by the refrigerant passing through saidvalve for raising the liquid from said vessel. v

13. In a refrigerating system having a compressor, a condenser, atop-feed trickle-type evaporator and conduits for connecting the same incircuit, a firstvessel connected to the bottom of said evaporator forreceiving liquid which has passed through the evaporator, a secondvessel located at a higher level than said first vessel and connected todeliver refrigerant to the top of said evaporator, a gas equalizer pipeconnecting the gas spaces of said vessels, a valve for controlling thepassage of refrigerant from said condenser toward said evaporator, andmeans operated by the refrigerant passing through said valve for raisingliquid from said first vessel into said second vessel.

14, In a refrigerating system having a compressor, a condenser, atop-feed trickle type evaporator and conduits for connecting the same incircuit, a first vessel connected to the bottom of said evaporator forreceiving liquid refrigerant from the bottom of said evaporator, asecond vessel connected in the conduit between said condenser andevaporator for deliveringliquid refrigerant into the top of saidevaporator and also connected in said conduit between said evaporatorand compressor, and a gas equalizer pipe for connecting the gas spacesof said vessels and operative to permit reflux of liquid from saidsecond vessel into said first vessel before liquid in said second vesselrises to the level of the connections in said evaporator-compressor.

15. In a refrigerating system having a compressor, a condenser, anevaporator and conduits for connecting the same in circuit, a firstvessel for receiving liquid refrigerant which has passed through theevaporator, a second vessel located at a level above that of the firstvessel and connected in the conduit between the condenser and evaporatorfor delivering'refrigerant into said evaporator, an ejector operated byrefrigerant passing from said condenser to said second vessel forraising liquid from said first vessel into said second vessel, a valvelocated betweensaid condenser and said ejector, and remote control meansfor actuating said valve.

16. In a refrigerating system having a compressor, a condenser, anevaporator and conduits for connecting the same in circuit, a firstvessel for receiving liquid refrigerant which has passed ,through theevaporator, a second vessel located at a level above that of the firstvessel and connected in the conduit between the condenser and evaporatorfor delivering refrigerant into said evaporator, an ejector operated byrefrigerant passing from said condenser to said second vessel forraising liquid from said first vessel into said second vessel, a valvelocated between said condenser and said ejector, and thermostatic valvecontrol means for actuating said valve.

17. In a refrigerating system having a compressor, a condenser, anevaporator and. conduits for connecting the same in circuit, a firstvessel for receiving liquid refrigerant which has passed through theevaporator, a second vessel interposed in the conduit between thecondenser and the evaporator, an ejector connected in the conduitbetween the condenser and said second vessel and operated by therefrigerant flowing toward said second vessel for raising liquid fromsaid first vessel into said second vessel, a valve located in theconduit between the condenser and ejector, and means responsive to therise andfall of liquid level in said first vessel for closing andopening said valve.-

18. In a refrigerating system having a compressor, a condenser, anevaporator and conduits for connecting the same in circuit, a firstvessel for receiving liquid refrigerant which haspassed through theevaporator, a second vessel interposed in the conduit between thecondenser and the evaporator, an ejector connected in the conduitbetween the condenser and said second vessel and operated by therefrigerant flowing toward said second vessel for raising liquid fromsaid first vessel into said second vessel, a valve located in theconduit between the condenser and the ejector, means responsive to therise and fall of liquid level in said first. vessel for closing andopening said valve, and a gas equalizer pipe for connecting thegasspaces of said vessels.

19. In a refrigerating system, acompressor, a condenser, an evaporatorand conduits for connecting the same in circuit, a first and low-levelvessel for receiving liquid refrigerant which has passed through theevaporator, a second and high-level vessel connected in the conduitbetween the condenser and the evaporator for supplying liquidrefrigerant to the evaporator and alsoconnected in the conduit betweenthe evaporator and compressor, and a valve operated in response to theliquid level in said first vessel .for controlling the fiow ofrefrigerant from the condenser into said second vessel.

20. In a refrigerating system having a compressor, a condenser, anevaporator and conduits for connecting the same in. circuit, low-leveland high-level vessels connected in series for liquid flow between thecondenser and evaporator, a valve-controlled conduit means forpermitting the movement of liquid refrigerant which has passed throughthe evaporator into said low- .level vessel and the escape offiashgas'from said low-level vessel, and valve means for controlling thepassage of refrigerant from said condenser into said low-level vessel.

21. In a refrigerating system having a compressor, a condenser, anevaporator and conduits for connecting the same in circuit, low-leveland high-level vessels connected in series for liquid flow between thecondenser and evaporator, conduit means having control valve means forpermitting the movement of liquid refrigerant which has passed throughthe evaporator into said lowlevel vessel and the escape of flash gasfrom said 1ow-level vessel, an expansion valve for controlling thepassage of refrigerant from said condenser into said low-level vessel,and means for intermittently opening and closing said control valve.

22. In a refrigerating system having a compressor, a condenser, anevaporator and conduits for connecting the same in circuit, low-leveland high-level vessels connected in series for liquid fiow between thecondenser and evaporator, conduit means having control valve means forpermitting the movement of liquid refrigerant which has passed throughthe evaporator into said lowlevel vessel and the escape of flash gasfrom said low-level vessel, an expansion valve for controlling thepassage of refrigerant from said condenser into said low-level vessel;and means for intermittently and coordinately opening and closing saidvalves, in opposition to each other. 23. In a refrigerating systemhaving a compressor, a condenser, an evaporator and conduits forconnecting the same in circuit, a first vessel for receiving liquidwhich has passed through the 24. In a refrigerating system a compressor,a condenser, a top-feed trickle-type evaporator and conduits forconnecting the same in circuit, a first vessel connected tothe bottom ofthe evaporator for receiving liquid refrigerant which has passed throughthe evaporator, a second vessel connected in the conduit between thecondenser and evaporator for supplying refrigerant into said evaporator,a valve for controlling the fiow of refrigerant from the condenser intosaid second vessel, and a gas equalizer pipe for establishing opencommunication between the gas spaces of said vessels.

25. In a refrigerating system having a compressor, a condenser, and atop-feed trickle-type evaporator, a first vessel for receiving liquidrefrigerant which has passed through said evaporator; a second vessellocated at a higher level than said first vessel, a gas equalizer pipefor connecting the gas spaces of said vessels, a gas collector pipeconnected with saidevaporator for delivering gaseous refrigerant intothe gas space of said second vessel, 2. gas return conduit from saidsecond vessel to the compressor, a conduit for connecting the condenserwith said second vessel including a control valve, and a supply conduitfor connecting said second vessel to the top of said evaporator.

26. In a refrigerating system having a com- I pressor, a condenser, atop-feed trickle-type evaporator, a gas collector pipe connected to saidevaporator at a plurality. of vertically spaced points thereof, ahigh-level vessel in communication with said gas collector pipe, a gas'con- .duit connecting said high-level vessel with the compressor, aliquid supply conduit for connect-' ing said high-level vessel with thetop of the evaporator, a low-level vessel connected with the bottom ofthe evaporator for receiving liquid refrigerant which has passed throughthe evaporator, a liquid conduit for connecting said vessels whereby theliquid in said low-level vessel may be raised into said high-levelvessel, and means' operated by the transfer of refrigerant from a highpressure portion to a low pressure portion of the system for raisingliquid from the lowlevel vessel to the high-level vessel.

27. In a refrigerating system, a compressor, a condenser, a conduit forconnecting said compressor and condenser, an evaporator, a first.

vessel for receiving liquid refrigerant which has passed through saidevaporator, a scondvessel located at a higher level than said firstvessel, a conduit between the second vessel and the evaporator forsupplying liquid refrigerant to the latter, a conduit for establishingcommunication between said second vessel and said first vessel at apoint below a predetermined liquid level in the latter, an ejectornozzle located in said first 28. In a refrigerating system having acompressor; a condenser, anevaporator, a conduit for connecting saidcompressor and condenser, a first vessel for receiving liquidrefrigerant which has passed through said evaporator, a second vessellocated at a higher level than said first vessel and connected with theevaporator for supplying liquid refrigerant to the latter, a conduit forestablishing communication between said second vessel and said firstvessel at a point below a predetermined liquid level in the latter, anejector nozzle located in said first vessel in operative relation withthe mouth of said communication conduit, a conduit for connecting saidcondenser with said nozzle and including an expansion valve, anequalizing conduit for connecting the gas spaces of said vessels, andgas conduits for connecting said evaporator, second vessel andcompressor.

29. In a refrigerating system having a compressor, a condenser, anevaporator, a conduit for connecting said compressor and condenser, afirst vessel for receiving liquid refrigerant which has passed throughsaid evaporator, a second vessel located at a higher level than saidfirst vessel and connected with said evaporator for supplying liquidrefrigerant to the latter, a conduit for establishingcommunicationbetween said second vessel and said first vessel at a pointbelow a predetermined liquid level in the latter, an ejector nozzlelocated in said first vessel in operative relation with the mouth ofsaid communication conduit, a conduit for connecting said condenser withsaid nozzle and including an expansion valve, externally operable meansfor regulating the cross-section of passage in said nozzle, and gasconduits for 'onnecting said evaporator, second vessel and compressor.

NORMAN H. GAY.

